time delay relay

Discussion in 'General Electronics Chat' started by alim, Aug 22, 2009.

  1. alim

    Thread Starter Senior Member

    Dec 27, 2005
    113
    1
    Hi to all . I need some help, I had seen a circuit sometime back which I thought could serve my purpose , but has been unable to find it. What I need is to build a variable time delay circuit to operate a 110 volt relay . This would serve to apply power to a fridge with a delay of up to four mins after power has been restored, the timer has to work off 110 v maybe thru a small transformer if necessary. Thankalim.s for your help.
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    You can get off the shelf models from McMaster Carr, Grainger, or a number of other sources. If you want to do it yourself we can talk you through it though.
     
  3. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
    230
    alim,

    Google: "delay-on-make" relay timer

    Ken
     
  4. alim

    Thread Starter Senior Member

    Dec 27, 2005
    113
    1
    Hi yes I would like to do it myself, and would be happy for the guidance. alim
     
  5. KMoffett

    AAC Fanatic!

    Dec 19, 2007
    2,574
    230
    Off the top of my head....a 5-minute LMC555 monostable with a power-up trigger, driving a transistor (or MOSFET) that can drive a relay that can switch you refrigerator's voltage/current. This powered by a wall-wart.

    Like Bill Marsden's circuit (reply#3) in another thread: http://forum.allaboutcircuits.com/showthread.php?t=26943

    ken
     
    Last edited: Aug 23, 2009
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